Method for locating drifting submerged gear

ABSTRACT

A method for locating drifting gear, including at least the following steps: —anchoring a submerged beacon to one of the ends of the drifting gear, the submerged beacon being equipped to rise to the surface and including a casing enclosing a transceiver of a radio-acoustic signal associated with a control unit, and a release mechanism allowing the beacon to rise in response to reception of a code and an order by the control unit, —geolocating the start point of the drifting gear, in order to allow the fisherman to delineate the region of its location by estimating the drift of his drifting gear from the start point so as to direct the search for the drifting gear in the estimated direction, —locating the drifting gear using the submerged beacon.

TECHNICAL FIELD OF THE INVENTION

The object of the present invention is a method for locating against loss or vandalism drifting submerged fishing gear.

BACKGROUND

In the fishing field, using gear connected on the surface to a moving boat such as, for example, drag nets, seine nets or trawls is known. Using drifting gear connected solely to one or more buoys floating on the surface such as, for example, long lines is also known.

This fishing gear is certainly very effective but has the major drawback of being liable to drift in an uncontrolled manner or being liable to become drifting gear when it is wholly or partly lost following an abnormality such as partial destruction thereof or rupture of the connection thereof with the associated boat, these being caused by poor meteorological conditions, the nature of the sea bed and/or various obstacles located on the sea bed or between two stretches of water such as for example flotsam, large fish or cetaceans. This major drawback runs counter to the recent requirements of the FAO (Food and Agricultural Organisation), which is an intergovernmental organisation of the United Nations, one of the remits of which is to provide information and to harmonise standards in the fields of nutrition, agriculture, forests and fishing, in particular by means of its publications and its databases. This is because the FAO requires the fishing sector, in a report dated 2010, to do everything possible to recover fishing gear lost at sea in order in particular to avoid “phantom fishing”, which destroys the halieutic resource to a very great extent and for no purpose and which therefore has a very great ecological impact. Devices or methods such as those described in the international patent applications WO 98/45169, WO 2017/109416 and WO 2018/162537 and/or the American patent application U.S. Pat. No. 7,487,614 are already known. However, these devices or methods are not satisfactory.

SUMMARY

The aim of the present invention is therefore to propose a method for locating fishing gear that is drifting or is liable to drift, thus complying with the requirement of the FAO, by making it possible to quickly and easily locate said gear, whatever the relief of the sea bed and/or the meteorological conditions.

In this regard, the object of the present invention is a method for locating drifting gear that is remarkable in that it includes at least the following steps:

-   -   anchoring at least one submerged beacon to the drifting gear         that it is wished subsequently to locate, said submerged beacon         being provided with means that ensure it will rise to the         surface and comprising a casing enclosing a transceiver for a         radio-acoustic signal associated with a control unit coupled to         at least one time-measuring unit, and a release mechanism         enabling said beacon to rise to the surface in response to the         reception of a radio-acoustic code and an order from said         control unit,     -   geolocating the start point of the drifting gear by the owner         thereof, in order to enable the latter to limit the location         zone by estimating the drift of his drifting gear from the start         point so as to direct the search for said drifting gear in the         estimated direction,     -   locating the drifting gear by means of the submerged beacon.

The location step consists of the transmission by the transceiver of the submerged beacon of a radio-acoustic signal able to be received by a transceiver sensor of the owner of the drifting gear and the transmission by the probe of the radio-acoustic code allowing triggering of the release mechanism and the rising of said beacon to the surface, when the radio-acoustic signal is received by the probe.

The location step may also consist of the programmed release of at least one locating element secured to the submerged beacon followed by the rise of the latter to the surface.

The location step may also consist of the programmed triggering of the release mechanism enabling the submerged beacon to rise to the surface.

The location method advantageously includes, before the step of anchoring a submerged beacon, a step of inputting into the control unit the periodicity and the duration of the radio-acoustic signal transmitted by the submerged beacon and/or the date and time of the release of at least one location element and/or the triggering of the release mechanism enabling the submerged beacon to rise to the surface.

The location method includes, preferably, conjointly with the location step, a complementary step of assisting location by means of one or more location-assistance members attached to the submerged beacon and/or to the location element.

The invention furthermore relates to a submerged beacon implementing the method for locating drifting gear according to the invention, remarkable in that it includes:

-   -   a casing consisting of two half-shells connected together and         having an external form having a hydrodynamic profile with low         sensitivity to sea currents, said casing enclosing a transceiver         for a radio-acoustic signal associated with a control unit         coupled to at least one time-measuring unit,     -   a cable attached at one of the ends thereof to an anchoring         point of the drifting gear,     -   a release mechanism enclosed in a hermetic tank constituting a         buoyancy reserve withstanding predetermined pressures, said         release mechanism enabling said beacon to rise to the surface in         response to the reception of a radio-acoustic code and of an         order from said control unit, and     -   at least one energy source.

The submerged beacon advantageously includes at least one location element able to be released in order to rise to the surface, while remaining connected to it.

The submerged beacon preferably includes one or more location-assistance members attached to its casing and/or the location element.

DETAILED DESCRIPTION

The object of the present invention is a method for locating drifting fishing gear connected solely to one or more buoys floating on the surface and fishing gear connected to a moving boat and liable to drift following an abnormality such as partial destruction or rupture of the connection thereof with the boat, said fishing gear being for example drift nets, seine nets, long lines or trawls. In the present application all these types of at least partially submerged fishing gear will be referred to as “drifting gear”.

The method for locating drifting gear according to the invention includes a first step consisting in anchoring a submerged beacon to one of the ends of the drifting gear that it is wished subsequently to locate, said submerged beacon being provided with means enabling it to rise to the surface and comprising a casing containing a transceiver for a radio-acoustic signal associated with a control unit coupled to at least one time-measuring unit, and a release mechanism enabling said beacon to rise to the surface in response to the reception of a radio-acoustic code and of an order from said control unit.

It will be understood clearly that, under the normal conditions of use, the submerged beacon anchored to one of the ends of the drifting gear is disposed in the water and is not designed to float on the surface of the water. Said anchored submerged beacon will rise to the surface only under certain conditions described below in the present description. Said location method includes a second step consisting in geolocating, by means for example of a GPS (Global Positioning System) navigation aid, the start point of the drifting gear, in order to enable the fisherman to limit the location zone by estimating the drift of his gear drifting from the start point so as to direct the search for said drifting gear in the estimated direction.

According to an advantageous embodiment, said submerged beacon further includes:

-   -   a casing consisting of two half-shells connected together and         having an external form having a hydrodynamic profile,         advantageously in the rough form of an ellipsoid of revolution,         enabling it to be little sensitive to sea currents, said casing         enclosing a transceiver for a radio-acoustic signal and a         control unit,     -   a cable attached at one of its ends to an anchoring point of the         drifting gear,     -   a release mechanism enclosed in a hermetic tank constituting a         buoyancy reserve withstanding predetermined pressures, said         release mechanism advantageously being of the electromechanical         type and including a motor provided with a brake, incorporated         or not, and being able to rotate or lock a winding drum around         which said cable is wound, and     -   at least energy source procuring the electrical energy necessary         for the correct functioning in particular of said release         mechanism.

The submerged beacon is associated with a device for triggering the motor such as, for example, a remote control or a switch enabling the motor to be rotated in order to bring said submerged beacon to the predetermined set depth. This triggering device also makes it possible to disengage the brake and the motor, in order to make the winding drum free to rotate in the event of a problem during winding or to proceed with manual winding following a failure of the energy source or of one of the components of the release mechanism.

To ensure even winding of the cable, the submerged beacon is advantageously equipped with a cable guide that makes it possible to correctly distribute said cable around the winding drum.

The control unit of the submerged beacon in particular incorporates a pressure sensor and a time-measuring unit. The control unit may also incorporate a temperature sensor making it possible to correctly manage the discharge curves of the energy source and to trigger the submerged beacon in the event of a limit voltage.

Moreover, the submerged beacon advantageously includes at least one location element that, if needed, can be released in order to rise to the surface, while remaining connected to said submerged beacon, in order to communicate the position of the latter and of the associated drifting gear. Said location element advantageously includes one or more location-assistance members complying with current legislation and being such as, for example:

-   -   a flash lamp including at least one bulb disposed under a         transparent protective block attached to the top of a body         containing an electronic card associated with a shade sensor and         a pressure sensor, so that the flash lamp flashes only when it         is night-time and the flash lamp is out of the water, and/or     -   a transmitter connected to one or more systems for monitoring,         detecting and identifying ships such as, for example, the AIS         system (Automatic Identification System), the VMS system (Vessel         Monitoring System) or the VDS system (Vessel Detection System),         and/or     -   an indicator flag, and/or     -   a radar deflector, and/or     -   a geolocation antenna, for example a GPS antenna.

The submerged beacon may also include one or more location-assistance members attached to its casing and being similar to those of the releasable location element previously described.

This embodiment of the beacon has the advantage of no longer having to calculate the exact length of the cable to be deposited between the submerged beacon and the associated drifting gear, since the beacon is adjusted according to its actual depth with respect to the set depth by means of the pressure sensor, the control unit, the motor of the release mechanism and its associated brake, the variation in the actual depth being able to be related to the tidal range, to the current and to any reliefs on the seabed that might cause the drifting gear to fall, for example, to the bottom an undersea trench.

The location method then includes a third step consisting in locating the drifting gear by means of the associated submerged beacon.

To implement this third step, a first solution consists in switching the transceiver of the submerged beacon into transmission mode in order to transmit a radio-acoustic signal, coded or not, able to be received by a transceiver probe composed generally of at least one transducer for the transmitting part and a hydrophone for the receiving part, and conventionally disposed under the boat of the fisherman owning the drifting gear, the power of said signal is next analysed so as to communicate to the fisherman the approximate direction and/or position of the submerged beacon and of the associated drifting gear. This is because it will be understood clearly that, the stronger the radio-acoustic signal received by the hydrophone of the probe of the boat, the closer is the submerged beacon. As soon as the control unit coupled to the probe of the boat estimates that the radio-acoustic signal received is preferably optimum, i.e. sufficiently strong, it instructs the probe of the boat to go into transmission mode and to send with its transducer a specific radio-acoustic signal of sufficient power to be received by the submerged beacon and making it possible to trigger the release mechanism enabling said beacon to rise to the surface.

In order not to make demands on the energy source of the submerged beacon continuously, the third step of the location method is such that the transmission of the radio-acoustic signal transmitted by the submerged beacon is advantageously not continuous but on the contrary the transmission is periodic and limited to a predetermined duration, for example of the order of a few minutes.

To implement this third step, a second solution uses a location element secured to the submerged beacon and able to be released to enable it to rise to the surface, while remaining connected to said beacon. Release of said location element is advantageously programmed to a predetermined date and time by the fisherman.

Finally, a third solution consists in programming the measuring unit of the submerged beacon associated with the drifting gear so as to trigger, at a date and time predetermined by the fisherman, the release mechanism enabling the submerged beacon to rise to the surface, which, once on the surface, will, where necessary, activate one or more of its location-assistance members such as, for example, the transmitter connected to one or more systems for monitoring, detecting and identifying ships and/or the flash lamp permanently attached to its casing.

Each solution envisaged for implementing the third step of the location method described above can be implemented alone or conjointly with at least one of the other two solutions.

Thus the third step of the location method according to the invention may, for example, consist of the release and rising to the surface of a location element provided with a geolocation antenna and the transmission of a radio-acoustic signal by the transceiver of the submerged beacon including in particular the coordinates of the geolocation of the latter and being able to be received by the transceiver probe of the owner of the drifting gear, the whole being followed by the rising of said submerged beacon to the surface. It will be understood clearly that this configuration allows a quicker location of the submerged beacon and therefore of the associated drifting gear.

It will be understood clearly that the location method according to the invention is mainly used for locating drifting fishing gear.

Finally, it goes without saying that the examples of a location method according to the invention that have just been described are merely particular illustrations, under no circumstances limitative of the invention. 

1.-9. (canceled)
 10. A method for locating drifting gear, comprising: anchoring a submerged beacon to one of the ends of the drifting gear that it is wished subsequently to locate, said submerged beacon being provided with means that ensure it will rise to the surface and comprising a casing enclosing a transceiver for a radio-acoustic signal associated with a control unit coupled to at least one time-measuring unit, geolocating the start point of the drifting gear, in order to enable the fisherman to limit the location zone by estimating the drift of his drifting gear from the start point so as to direct the search for said drifting gear in the estimated direction, location of the drifting gear by the submerged beacon, the latter comprising a release mechanism enabling said beacon to rise to the surface in response to the reception of a radio-acoustic code and of an order from said control unit, said location step consisting of the transmission, by the transceiver of the submerged beacon, of a radio-acoustic signal able to be received by a transceiver probe of the owner of the drifting gear and the transmission by said probe of the radio-acoustic code enabling the triggering of the release mechanism and the rising of said beacon to the surface, when the radio-acoustic signal is received by the probe.
 11. The method for locating according to claim 10, wherein the location step consists of the programmed release of at least one location element secured to the submerged beacon followed by the rising of the latter to the surface.
 12. The method for locating according to claim 10, wherein the location step consists of the programmed triggering of the release mechanism enabling the submerged beacon to rise to the surface.
 13. The method for locating according to claim 10, wherein before the step of anchoring a submerged beacon, a step of inputting into the control unit the periodicity and the duration of the radio-acoustic signal transmitted by the submerged beacon and/or of the date and time of the release of at least one location element and/or of the triggering of the release mechanism enabling the submerged beacon to rise to the surface.
 14. The method for locating according to claim 10, wherein conjointly with the location step, a complementary step of assisting location by one or more location-assistance members attached to the submerged beacon and/or the location element. 